1. Field of the Invention
The invention relates to a playback method and apparatus for reading audio programs that were recorded on a record carrier.
2. Description of the Related Art
In a co-pending U.S. patent application, entitled xe2x80x9cRecord Carrier, and Recording Method and Apparatus for Recording Audio Programs on a Track of a Record Carrier,xe2x80x9d and filed by the Applicant, there is disclosed a record carrier, such as a compact disc, which includes a number of tracks having a number of blocks. As shown in FIG. 1, each block (B) includes a plurality of interleaved compressed audio programs, and is grouped into a number of consecutive sub-blocks. Each of the compressed audio programs is segmented to form a number of consecutive audio sectors (AS(i,j), i=0 to 5, j=0 to kxe2x88x921) that is equal in number to the sub-blocks. The audio sectors AS(i,j) of the compressed audio programs are arranged among the sub-blocks such that a jth one of the audio sectors AS(i,j) of each of the compressed audio programs is disposed in a jth one of the sub-blocks.
The compressed audio programs are assigned with an ascending order of program numbers, and the audio sectors AS(i,j) in each of the sub-blocks are arranged in the ascending order of the compressed audio programs to which the audio sectors AS(i,j) belong. As shown in FIG. 2, each of the audio sectors AS(i,j) includes a SYNC field 10 for storing a SYNC word, an ID field 11 for storing an ID code that is unique for each of the audio sectors AS(i,j), a data field 12, and an error management code field 13 for storing an error management code.
Referring to FIG. 3, the ID field 11 includes a track number (TN), a block number (BN), a program number (PN), a sector number (SN), and connection information (CI). The track number (TN) indicates the track (T) of the record carrier to which the audio sector AS(i,j) belongs. The block number (BN) indicates the block (B) on the track to which the audio sector AS(i,j) belongs. The program number (PN) indicates the compressed audio program on the block (B) to which the audio sector AS(i,j) belongs, e.g. i=0 to 5 as shown in FIG. 1. The sector number (SN) indicates the sector number of the audio sector AS(i,j) in the compressed audio program to which the audio sector AS(i,j) belongs, e.g. j=0 to kxe2x88x921 as shown in FIG. 1. The connection information (CI) contains flags for facilitating continuous playback of the compressed audio programs when the record carrier is read. The flags can include an end of program (EOP) flag, an end of block (EOB) flag, an end of track (EOT) flag, and an end of disc (EOD) flag. Particularly, the last audio sector of each of the compressed audio programs, i.e. AS(i,kxe2x88x921), has an EOP flag. The last audio sector of each block (B), i.e. AS(5,kxe2x88x921), further has an EOB flag. The last audio sector AS(5,kxe2x88x921) of the last block (B) in a track further has an EOT flag. The last audio sector AS(5,kxe2x88x921) of the last block (B) in the last track of the record carrier further has an EOD flag.
By virtue of the interleaving arrangement of the audio sectors on the record carrier, a high density of compressed audio programs can be recorded on tracks of the record carrier while retaining the constant linear velocity, i.e. 1.5 Mbits/sec, of a compact disc drive with a compressed audio bit rate of about 224 Kbits/sec, thereby obviating the need for the compact disc drive to alternate frequently between stalling and advancing states to minimize degradation of the compact disc drive when the compressed audio programs are read from the record carrier.
The object of the present invention is to provide a playback method and apparatus for reading audio programs that were recorded on the record carrier described beforehand.
According to this invention, a playback apparatus is capable of reading a record carrier having at least one track. The track has at least one block. The block includes a plurality of interleaved audio programs and is grouped into a number of consecutive sub-blocks. Each of the audio programs is segmented to form a number of consecutive audio sectors that is equal in number to the sub-blocks. The audio sectors of the audio programs are arranged among the sub-blocks such that a jth one of the audio sectors of each of the audio programs is disposed in a jth one of the sub-blocks. Each of the audio sectors includes an ID field for storing an ID code that is unique for each of the audio sectors, and a data field. The playback apparatus comprises drive means, an ID extractor, a retrieval controller, and a sector data extractor. The drive means is adapted to send out the audio sectors that were recorded on the record carrier. The ID extractor is connected to the drive means for extracting the ID codes of the audio sectors that were sent out by the drive means. The retrieval controller is connected to the ID extractor to receive the ID codes extracted thereby. The sector data extractor is connected to the drive means and the retrieval controller, and receives the data fields of the audio sectors that were sent out by the drive means. The sector data extractor is controlled by the retrieval controller to extract the data fields of appropriate ones of the audio sectors when the ID codes thereof are recognized by the retrieval controller as belonging to a selected one of the audio programs.
In one aspect of the invention, a playback method for reading a block of a track of a record carrier comprises:
(a) sending out the audio sectors of the block;
(b) extracting the ID codes of the audio sectors that were sent out;
(c) extracting appropriate ones of the audio sectors when the ID codes thereof are recognized as belonging to a selected one of the audio programs;
(d) upon recognition of an end-of-program flag in the ID code of a last one of the audio sectors of the selected one of the audio programs, resending the audio sectors of the block;
(e) repeating steps (b) and (c) to extract the audio sectors that belong to another one of the audio programs; and
(f) repeating steps (d) and (e) to extract the audio sectors of other ones of the audio programs until an end-of-block flag in the ID code of the last one of the audio sectors of a last one of the audio programs in the block is recognized.
In another aspect of the invention, a playback method for reading the blocks of a track of a record carrier comprises:
(a) sending out the audio sectors of a selected one of the blocks;
(b) extracting the ID codes of the audio sectors that were sent out;
(c) extracting appropriate ones of the audio sectors when the ID codes thereof are recognized as belonging to a selected one of the audio programs;
(d) upon recognition of an end-of-program flag in the ID code of a last one of the audio sectors of the selected one of the audio programs in the selected one of the blocks, sending out the audio sectors of another one of the blocks;
(e) repeating steps (b) and (c) to extract the audio sectors that belong to a selected one of the audio programs of said another one of the blocks;
(f) repeating steps (d) and (e) to extract the audio sectors that belong to a selected one of the audio programs of other ones of the blocks until the end-of-program flag in the ID code of the last one of the audio sectors of the selected one of the audio programs in a last one of the blocks of the track is recognized;
(g) resending the audio sectors of the track;
(h) repeating steps (b) to (f) to extract the audio sectors of another one of the audio programs in each of the blocks; and
(i) repeating steps (g) and (h) to extract the audio sectors of other ones of the audio programs in each of the blocks until an end-of-track flag in the ID code of the last one of the audio sectors of a last one of the audio programs in the last one of the blocks of the track is recognized.
In still another aspect of the invention, a playback method for reading tracks of a record carrier comprises:
(a) sending out the audio sectors of one of the blocks of a selected one of the tracks;
(b) extracting the ID codes of the audio sectors that were sent out;
(c) extracting appropriate ones of the audio sectors when the ID codes thereof are recognized as belonging to a selected one of the audio programs;
(d) upon recognition of an end-of-program flag in the ID code of a last one of the audio sectors of the selected one of the audio programs, sending out the audio sectors of another one of the blocks of the selected one of the tracks;
(e) repeating steps (b) and (c) to extract the audio sectors that belong to a selected one of the audio programs of said another one of the blocks;
(f) repeating steps (d) and (e) to extract the audio sectors that belong to a selected one of the audio programs of other ones of the blocks of the selected one of the tracks until the end-of-program flag in the ID code of the last one of the audio sectors of the selected one of the audio programs in a last one of the blocks of the selected one of the tracks is recognized;
(g) sending out the audio sectors of one of the blocks of another one of the tracks;
(h) repeating steps (b) to (f) to extract the audio sectors of a selected one of the audio programs in each of the blocks of said another one of the tracks;
(i) repeating steps (g) and (h) to extract the audio sectors of a selected one of the audio programs in each of the blocks of other ones of the tracks until the end-of-program flag in the ID code of the last one of the audio sectors of the selected one of the audio programs in the last one of the blocks of a last one of the tracks of the record carrier is recognized;
(j) resending the audio sectors of the tracks of the record carrier;
(k) repeating steps (b) to (i) to extract the audio sectors of another one of the audio programs in each of the blocks in each of the tracks of the record carrier; and
(l) repeating steps (j) and (k) to extract the audio sectors of other ones of the audio programs in each of the blocks in each of the tracks of the record carrier until an end-of-disc flag in the ID code of the last one of the audio sectors of the last one of the audio programs in the last one of the blocks of the last one of the tracks of the record carrier is recognized.